Variable pitch propeller



Sept. 27, 1966 N. J. ALLIN 3,275,083

VARIABLE PITCH PROPELLER 7 Filed Oct. 15, 1965 2 sheets sheet 1 m/x a/vrak Sept. '27, 1966 N, ALUN 3,275,083

VARIABLE PITCH PROPELLER Filed Oct. 15, 1965 v 2 Sheets-Sheet 2 United States Patent 3,275,083 VARIABLE PITCH PROPELLER Norman J. Allin, Hermosa Beach, Calif., assignor to Bradley A. Kendis, trustee Filed Oct. 15, 1965, Ser. No. 496,549 6 Claims. (Cl. 170-16013) This invention relates to a variable pitch propeller, and more particularly, refers to such a propeller in which pitch changes are accomplished solely by momentarily, interrupting the driving power.

While the invention is applicable for its purpose to propellers which act upon air as well as propellers which act upon water, the initial embodiment of the invention is a marine propeller. This initial embodiment has been selected for the present disclosure and will provide adequate guidance to those skilled in the art who may have occasion to apply the same principles to propellers acting on air.

In a variable pitch propeller of this particular type, each propeller blade is mounted on the hub structure of the propeller in a rotatable manner for changes in pitch adjustment and the center of pressure against the blade by the ambient fluid is ofiset from the axis of pitch adjustment. With this relationship between the center of pressure and the axis of pitch changes, the pressure of the ambient fluid against the rear surface of the blade when the propeller is power driven tends to change the pitch of the blade in one respect and the opposite pressure of the ambient fluid against the forward face of the blade when the blade is dragged through the water without power tends to change the pitch of the blade in the opposite respect. Advantage is taken of these opposite efiects on the blade of the propeller to cause the pitch of the blade to change in response to an operation which consists merely of cutting off the driving power and then restoring the driving power.

Various mechanisms for this purpose have been suggested in the prior art, but, in general the mechanisms are complicated and consequently costly. One pn'or mechanism which is less complicated than most is divided into two parts with limited rotation between the two parts, one part being a driving part and the other part being a driven part that carries the propeller blade. In this arrangement, the lost motion between the two parts causes the driven part to overrun the driving part when the applied power is interrupted, the driving part subsequently falling back to its normal position when power is resumed.

This oscillation of the driven part relative to the driving part created by a momentary interruption in the applied power oscillates a ratchet to rotate a pitch-changing ring by one increment. A continuous cam slot on the periphery of the pitch-changing ring serves to change the pitch of the propeller blade, the intermittent rotations of the pitch-changing ring changing the pitch alternately in opposite respects. Thus a change from relatively high pitch to relatively low pitch may be carried out by merely interrupting the driving power and the change back from the relatively low pitch to the relatively high pitch may be accomplished by again momentarily interrupting the driving power.

The present invention achieves the ultimate in simplification by eliminating the lost motion between the applied power and the propeller and by relying solely on the two opposite moments that are applied to the propeller blade by the pressure of the ambient fluid when the applied power is interrupted and then resumed.

This simplification is achieved by incorporating two rotatable rings in the hub structure. The first of the two rings is operatively connected to each of the propeller blades to oscillate in response to oscillation of the propeller blades when the applied power is interrupted and then resumed. The second ring, which is positioned face-to-face beside the first ringis rotatably advanced by one increment or step by each oscillation of the first ring, a ratchet mechanism being effective between the two rings for this purpose. Thus an oscillation of the propeller blades caused by momentarily interrupting the applied power causes the second ring to rot-ate a fraction of a revolution relative to the first ring.

For the purpose of operatively connecting the two rings to the propeller blades, the confronting faces of the two rings are notched to cause the two rings to cooperate to form a plurality of peripheral cavities corresponding to the plurality of propeller blades and each blade has an eccentrically located cont-rol finger extending into a corresponding cavity. When the propeller blades are oscillated by momentary interruption of the power, the control fingers of the blades oscillate the first ring to advance the second ring one step relative to the first ring.

The cavities formed by the cooperating notches in the two rings change in size in response to the stepping of the second ring relative to the first ring, the successive steps causing the cavities to increase and decrease in size alternately. When the cavities are relatively large, they cooperate with the control fingers to maintain the blades at relatively high angles of pitch adjustment and when the cavities are relatively small they cooperate with the control fingers to maintain the blades at relatively low pitch angles.

The various features and advantages of the invention may be understood from the following detailed description together with the accompanying drawings.

In the drawings, which are to be regarded as merely illustrative:

FIG. 1 is an elevational view of the rear face of a propeller embodying the presently preferred practice of the invention;

FIG. 2 is a side elevation of the propeller;

FIG. 3 is an axial section of the hub structure taken along the line 3-3 of FIG. 1;

FIG. 4a is a somewhat schematic fragmentary view of the hub structure as seen along the line 4-4 of FIG. 3, the view showing a control finger of a blade as positioned for maintaining the propeller blade at a relatively high pitch angle;

[FIG. 4b is a similar view showing the first pitch-changing ring in the position to which it is moved by the control fingers when the applied power is interrupted;

FIG. 4.0 is a similar view showing how the resumption of the applied power returns the first pitch-changing ring to its normal position to complete the shift of the propeller blade from the relatively high pitch angle to an alternate relatively low pitch angle;

tapered head 25.

FIG. 5 is a cross section along the line 55 of FIG. 3 showing detent recesses in the face of the second pitchchanging ring; I

FIG. 6 is a cross-sectionalview along the line 6- 6 of FIG. 3 showing the ratchet teeth and finger-engaging recesses on the face of the second pitch-changing ring;

FIG. 7 is a similar view along the same line but looking in the opposite direction as indicated at 77 in FIG. 3, the view showing the ratchet teeth and finger-engaging recesses in the face of the first pitch-changing ring; and

FIG. 8 is a perspective view showing the cooperating faces of the two rings.

FIG. 3 shows in section a hub structure which is fixedly mounted on a drive shaft 10. This fixed hub structure includes the following parts: an inner sleeve 12 embracing shaft 10, one end of the sleeve being formed with a flange 14 and the other end ofthe sleeve being fixed relative to the shaft by a transverse shear pin 15; a. stepped sleeve 16 that embraces the inner sleeve 12 and is'norby a compressed resilient collar 18 of elastomeric ma terial; a pair of abutting annular members 20 and 22 which are releasably secured together and are additionally anchored to the stepped sleeve 16 by suitable screws 24; and a tapered head 25 which is mounted on the screw thread of a reduced end 26 of the shaft 10.

The two annular members 20 and 22 cooperate to form a plurality of sockets 28 for journaling the root portions 30 of a corresponding plurality of propeller blades 32. In this particular embodiment of the invention there are three propeller blades 32. Each of the three sockets 28 -is,formed with an inner enlargement 34 to confine a similar enlargement or flange 35 of the root portion 30 of the corresponding propeller blade.

It is. apparent that each of the propeller blades 32 is rotatable for pitch adjustment about an axis, which axis is indicated in broken lines at 36 in FIGS. 1 and 3 and it is important to note that the center of pressure of each blade is positioned eccentrically of the blade axis 36,'the

centers of pressure being indicated at 38 in FIG. 1. When the propeller blades are acting under power against-the ambient water to drive the boat to the left as the propeller is viewed in FIG. 2, the pressure of the water is against the rear faces of the propeller blades and with the centers of pressure 38 offset from the blade axes 36 the water creates moments that tend to turn each blade clockwise. On the other hand when the boat is moving forward under momentum but without power, the dragging of the blades through the water causes the pressure of the water to act on the forward faces of the blades and the eccentrically located centers of pressure result in the application of counterclockwise moments to the blades. As best shown in FIG. 3, each of the three propeller blades 32 has an eccentrically positioned control finger 40 which moves in an are when the blade changes in pitch. The control fingers 40 of the propeller blades 32.

cooperate with a pair of pitch-changing rings comprising a first ring 41 and a second ring 42, the two rings being rotatably mounted on the previously described hub structure.

The face of the first pitch-ringing ring 41 which confronts the second pitch-changing ring 42 is formed with a circular series of ratchet teeth 44 and is further formed with three recesses 45 at equal circumferential spacing. In similar manner the face of the second pitch-changing ring 42 that confronts the first pitch-changing ring 41 is formedwith a circumferential series of ratchet teeth 46' and is further formed with a series of equally circumferentially spaced recesses 48.- To make the ratchet. teeth effective the first ring 41 is slidingly'as well as rotatably mounted and is continuously urged towards the second ring 42 by a coil spring 50 which backs against the It is contemplated that each pitch change, that is carrled out in each pitch-changing operation will involve which is indicated at A is relatively small.

oscillation of the first pitch-changing ring41 through an' angle of slightly more than 30 and the second ring 42 will be advanced 30 by each oscillation of the first ring.

For this purpose there may be six ratchet teeth or any multiple of sixratchet teeth on each of the two rings,

twelve ratchetteeth being shown in FIG. 2.

For the desired ratchet action to cause thesecond ring 42 to be rotated intermittently by the successive oscillations of the first ring .41, it is essential that the second ring 42 remain stationary when the first ring is rotated oppositely from its driving direction. .For this purpose any suitable means may be providedto create frictional resistance to oppose rotation of the ring ;42. In this particular embodiment of the invention,the,required frictional resistance. is provided by a detent means which comprises six detent recesses 52 on the rear face of the second ring 42 ('FIG. 5) and a cooperating detent ball 54. As shown in FIG. 3 the detentball 54 is mounted in a bore, 55 in the annular member-22 and'is urged'towards the ring 42" by aconfined spring 56'.

FIGS. 4a and 4b'show two relative positions of the. two

rings 41 and 42 which'occur alternately at .the end of successive oscillations of thefirst ring 41. In view 4a each of three recesses 45in'the' ring 41-cooperates with driven to move the boat for- .peller blade-tends to rotate the blade clockwise aboutits" axis withithe result that the.control fingers 40 of the. blades press against the ring 42. If under these circumstances the control finger 40 of each propeller blade is.

confined by a relatively large cavity 58 as shown inFIG. 4a the control finger presses against the inner surface of a recess 48 of the second control fingeras shown in FIG. 4a and the angle of pitch of the propeller blade on the other hand if the propeller is power driven while the'control finger 40 of each propeller blade is in a relatively small cavity 45 asshown in FIG; 40, each control finger 40 rests against a blank portion of the size of. the. second ring 42 to maintain the corresponding propeller blade at the relatively large pitch angle designated Bl It is apparent that each time the applied. power is interrupted, the resultant counterclockwise rotation of the three blades 32 will cause the three control fingers 40 to abut surfaces of the recesses 45 to rotate the ring 41 through an arc in one direction and the resumption of power will cause the three control fingers to act oppositely to return the ring 41 through the .same arc, the

extent of the arc determining a range of oscillation ofthe ring 41 and the consequent range of intermittent advance for each blade suitably located on the annular member 20, such a stop lug being shown at 62 in FIG. 2.1

The manner in which theinv'ention functions for its 7 purpose may be. readily understoodfrom the foregoing.

description. With the propeller under power with: each of the blades at the high pitch angle, A. as shown in FIG. 4a, the application of power is again interrupted to cause the propellers to oscillate. the ring 41 thereby to re turn the two rings 41 and 42 to the relationship shown in- FIG. 4a.

My description in specific detail of the presently preferred embodiment of the invention will suggest various changes, substitutions and other departures from my disclosure within the spirit and scope of the appended claims.

I claim:

1. In a variable pitch propeller driven by applied power to act on ambient fluid, the combination of:

a rotary hub structure adapted to be driven by the applied power;

a plurality of blades rotatably mounted on the hub structure for adjustment in pitch,

each of said blades having a finger spaced radially from its axisof pitch adjustment,

a portion of the rotary hub structure being rotatable relative tothe rest of the hub structure and being responsive to the fingers of the bladesto change to two different states alternately in response to successive oscillations of the blades about their pitch axes,

said portion of the hub structure at its two states confining the fingers of the blades at two diflerent pitch adjustments of the blades,

whereby the pitch of the blades may be changed from one of the alternate pitch adjustments to the other by interrupting the applied power and then again applying the power to cause thhe ambient fluid to create successive opposite moments on the propellers to oscillate the propellers thereby to change the state of said portion of the hub structure.

2. In a variable pitch propeller driven by applied power to act on ambient fluid, the combination of:

a rotary hub structure adapted to be driven by the applied power;

a plurality of blades rotatably mounted on the hub structure for adjustment in pitch,

each of said blades having a finger spaced radially from its axis of pitch adjustment;

a first ring member mounted on the rotary hub structure for rotation relative thereto;

a second ring member mounted on the hub structure for rotation relative thereto, said two ring members being adjacent each other with confronting faces;

ratchet means operative between the two members to cause movement of the first member in one rotary direction to drive the second member in the same rotary direction and to permit the first member to rotate in the opposite direction independently of the second member, whereby repeatedly oscillating the first member drives the second member intermittently in said one rotary direction; and

circumferentially spaced recesses in the confronting faces of the two ring members, respectively, the recesses of the two annular members cooperating to form cavities confining the respective fingers of the blades, each cavity being formed at least in part by a recess in said first member, the two annular ring members cooperating to change the cavities to relatively large size and to relatively small size alternately when the second member is rotated intermittently,

said control fingers being positioned relative to the axis of pitch adjustment of the corresponding blades to cooperate with the inner surfaces of the recesses in said first member to reciprocate the first member in response to changes to pitch of the propeller when the applied power is interrupted to cause the ambient fluid to change the pitch of the propellers and then the driven power is resumed to cause the ambient fluid to tend to restore the pitch,

the cavities at their relatively large size cooperating with the control fingers to maintain a first pitch adjustment of the propellers and at their relatively small size cooperating with the control fingers to maintain a second pitch adjustment.

3. A combination as set for in claim 2 which includes stop means on the hub structure to limit the oscillation of the propellers about their pitch axes.

4. In a variable pitch propeller driven by power to act on ambient fluid, the combination of:

a rotary hub structure adapted to be driven by the power;

a plurality of blades rotatably mounted on the hub structure for adjustment in pitch,

each of said blades having a pitch control finger spaced radially from its axis of pitch adjustment;

a first ring member rotatably mounted on the rotary hub structure for rotation relative thereto;

a second ring member rotatably mounted on the hub structure for rotation relative thereto, said two ring members being adjacent each other with confronting faces;

ratchet means operative between the two members to cause movement of the first member in one rotary direction to drive the second member in the same rotary direction and to permit the first member to rotate in the opposite direction independently of the second member, whereby repeatedly oscillating the first member drives the second member intermittently in said one rotary direction;

a first series of circumferential recesses in the mating face of said first member, one for each propeller, and a second series of circumferential recesses in the mating face of the second member,

the recesses of the two series being spaced to register with each other and not to register with each other alternately when the second member rotates interrnittently,

whereby the two members cooperate to form relatively large cavities and relatively small cavities alternately when the second member rotates intermittently,

said cavities confining the control fingers to maintain a first pitch adjustment when the cavities are relatively large and confining the control fingers to maintain a second pitch adjustment when the cavities are relatively small,

said control fingers cooperating with the first series of recesses to oscillate the first member in response to interruption and subsequent resumption of the driving power, the interruption causing the ambient fluid to create moments in one direction on the propellers and the resumption of power creating opposite moments on the propellers.

5. A combination as set forth in claim 4 which includes means to yieldingly resist rotation of the second ring.

6. In a variable pitch propeller driven by power to act on ambient fluid, the combination of:

a rotary hub structure adapted to be driven by the power;

a plurality of blades rotatably mounted on the hub structure for adjustment in pitch,

each of said blades having a pitch control finger spaced radially from its axis of pitch adjustment;

a first ring member rotatably mounted on the rotary hub structure for rotation relative thereto;

a second ring member rotatably mounted on the hub structure for rotation relative thereto, said two ring members being adjacent each other with confronting faces;

ratchet means operative between the two members to cause movement of the first member in one rotary direction to drive the second member in the same rotary direction and to permit the first member to rotate in the opposite direction independently of the second member, whereby repeatedly oscillating the first member drives the second member intermittently in said one rotary direction,

whereby the one member may be caused to oscillate by first terminating the power and then resuming the power thereby to cause the ambient fluid to create successive opposite moments on the propellers,

said two members having cooperating surfaces to form cavities with the cavities relatively large and relatively small alternately at the ends of the successive intermittent movements of the second member,

said control fingers extending into the cavities to maintain a first pitch adjustment when the cavities are relatively large and to maintain a second pitch adjustment when the cavities are relatively small.

References Cited by the Enaminer UNITED STATES PATENTS FOREIGN PATENTS Great Britain.

MARTIN P. SCHWADRON, Primary Examiner.

15 E. A. POWELL, JR., Assistarit Examiner. w 

1. IN A VARIABLE PITCH PROPELLER DRIVEN BY APPLIED POWER TO ACT ON AMBIENT FLUID, THE COMBINATION OF: A ROTARY HUB STRUCTURE ADAPTED TO BE DRIVEN BY THE APPLIED POWER; A PLURALITY OF BLADES ROTATABLY MOUNTED ON THE HUB STRUCTURE FOR ADJUSTMENT IN PITCH, EACH OF SAID BLADES HAVING A FINGER SPACED RADIALLY FROM ITS AXIS OF PITCH ADJUSTMENT, A PORTION OF THE ROTARY HUB STRUCTURE BEING ROTATABLE RELATIVE TO THE REST OF THE HUB STRUCTURE AND BEING RESPONSIVE TO THE FINGERS OF THE BLADES TO CHANGE TO TWO DIFFERENT STATES ALTERNATELY IN RESPONSE TO SUCCESSIVE OSCILLATIONS OF THE BLADES ABOUT THEIR PITCH AXES, SAID PORTION OF THE HUB STRUCTURE AT ITS TWO STATES CONFINING THE FINGERS OF THE BLADES AT TWO DIFFERENT PITCH ADJACENT OF THE BLADES, WHEREBY THE PITCH OF THE BLADES MAY BE CHANGED FROM ONE OF THE ALTERNATE PITCH ADJUSTMENTS TO THE OTHER BY INTERRUPTING THE APPLIED POWER AND THEN AGAIN APPLYING THE POWER TO CAUSE THE AMBIENT FLUID TO CREATE SUCCESSIVE OPPOSITE MOMENTS ON THE PROPELLERS TO OSCILLATE THE PROPELLERS THEREBY TO CHANGE THE STATE OF SAID PORTION OF THE HUB STRUCTURE. 